At present, cover-type metallic caps are formed by a laminated piece with a circular inner- and outer-face layout, from whose edge a peripheral skirt extends in a descending manner and to which a safety ring is attached by a series of bridges, and a gasket attached to the inner face of the circular layout and provided with a flat central zone and an annular zone, including an outer rim and an inner rim separated by a notch. These metallic cover caps are used to seal a threaded opening of a glass bottle containing a beverage, whether pressurized or not, since the thread that is formed on the skirt of the cover cap serves to engage with the outer thread of the opening of the glass bottle, while the safety ring attached to the skirt is an indicator of improper tampering with the bottle.
When the metallic cover cap is placed on the threaded opening of the glass bottle, the skirt and the safety ring are formed by means of a rolling process, in such a way that the skirt acquires a threading that interengages with the outer thread of the opening of the glass bottle, while the safety ring is deformed inwardly by gripping the lower surface of the gripping ring of the opening of the glass bottle, allowing a splice coupling between the sealing surface of the opening of the glass bottle and the gasket. More particularly, the sealing surface of the opening of the glass bottle is housed in the notch of the annular zone of the gasket; at this point, the outer edge of the sealing surface of the opening of the glass bottle engages the inner surface of the outer rim of the annular zone of the gasket, while the inner edge of the sealing surface of the mouth of the glass bottle engages with the inner surface from the inner rim of the annular zone of the gasket, thus ensuring a lateral seal on both sides of the notch, so that the plastic material of the gasket is deformed by the pressure exerted inside the glass bottle. The engagement of the notch and of the outer and inner rims over the sealing surface of the mouth of the glass bottle prevents the beverage contained within the glass bottle from escaping.
The current metallic cover cap that is used to seal the mouth of a glass bottle is not fit for sealing a mouth of a metal bottle, because the mouth of a metallic bottle has a different configuration to the configuration of a mouth of a glass bottle, as observed in FIGS. 1, 2, and 3. The opening 10 of a glass bottle has a sealing surface 11 with an outer diameter D1 and an inner diameter D2, an outer thread 12, and a gripping ring 15. The sealing surface 11 has an outer edge 13 and an inner edge 14 where the outer rim and the inner rim of the annular region of the metallic cover cap are respectively seated by the proper obstruction and sealing of the mouth once the metallic cover cap is screwed on.
In contrast therewith, the threaded opening 20 of a metallic bottle has a contoured sealing surface 21 with an outer diameter D1 and an inner diameter D2, an outer thread 22, and a gripping ring 25. The sealing surface 21 has an outer edge 23 and an inner edge 24. The outer diameter D3 is generally equal to the inner diameter D1 of the sealing surface 11 of the glass bottle 10, while the inner diameter D4 is greater than the outer diameter D2 of the sealing surface 11 of the glass bottle 10.
In addition to the above, by reason of its manufacturing process, the threaded mouth of the glass bottle has a constant diameter and its material has a resistance that does not allow deformation of the mouth during storage, transportation, filling, and sealing of the glass bottle, which favors the proper seating and airtight closing of the metallic crown-type cap. The configuration of the mouth of the glass bottle is standardized by the “Glass Packaging Institute.” In contrast, the threaded mouth of the metallic bottle, in particular the sealing surface, tends to deform in its own manufacturing process, as well as in the storage, transportation, filling, and sealing of the metallic bottle. This implies that the diameter of the threaded mouth of the metallic bottle has variations or irregularities that can cause a non-airtight closing of the traditional metallic crown-type cap.
It is therefore, that the metallic cover cap currently used to seal glass bottles is not at all suitable for sealing metal bottles, as the current cover cap gasket is not fit to compensate for the variations present in the finish and the diameter of the sealing surface of the threaded mouth of the metal bottle; so, providing a metallic cover cap with a gasket whose design compensates for said imperfections in the threaded mouth of the metal bottle is required.